This invention relates to a fan motor, particularly to one simple in structure, and able to supply a stable and large current for a power system and lower producing cost.
Conventionally, the power circuit of a control circuit system of an electric fan is classified into three kinds. The first one, as shown in FIG. 1, is a resistance drop device, in which a plurality of resistances R1-R4 are connected with each other in parallel at the input of a system power (AC input) to lower the input voltage of the control circuit system. Then, this input voltage is converted into a direct current power (VCC) through a rectified circuit to supply a control circuit for an entire electric fan (inclusive of its swinging head) with power.
The second one, as shown in FIG. 2, is a capacitance drop device, in which a capacitor (C3) is provided at the input of the alternating current (AC input) to lower the voltage of the input, which is then converted into direct current power (VCC) through the rectified circuit to supply sequently a control circuit with power.
The third one, as shown in FIG. 3, is to provide a transformer T at the input of the alternating current (AC input). The transformer T is able to directly and stably lower the voltage of the AC input power, and then this lowered voltage is converted into direct current power (VCC) through the rectified circuit to supply sequently a control circuit with power.
However, the first and the second conventional fan motor respectively having a resistance and a capacitance drop device are comparatively applicable to a control circuit system of small current (around 15 m amperes), able to reduce producing cost, but possible to limit practicability due to its supplying only a small current.
The third conventional fan motor provided with a transformer is able to supply a stable and large current for a power, but its producing cost may increase one fifth to one third, not conforming to economic gain.
The objective of the invention is to offer a fan motor simple in structure, and able to supply a stable and large current for a power system and lower producing cost.
The feature of the invention is that the stator coil of a single-phase motor has its starting coil or rotating coil provided with an auto-coupling tapped coil or a third coil to form a secondary coil to supply a voltage value for the power of a control circuit, having function of supplying a stable and large current for a power system and applicable to electric fans or other appliances.